Split ring slips , slotted unibody slips, multi-segment interlocking slips and methods of making the same

ABSTRACT

Multiple inventions for slips for use in settable downhole tools, for use in oil and gas wells are disclosed. Slips help lock the settable tool to an adjacent casing. In some embodiments, injection moldable interlocking slip segments are provided for use in a multi-segmented dissolvable slip in a downhole tool. In some embodiments, a slip with a single full split is provided that, during setting, expands at the split rather than breaking apart.

This application claims the benefit of and priority to US Provisional Application No. 62/573,982, filed Oct. 18, 2017. This application is a continuation-in-part of U.S. application Ser. No. 14/677,242, filed Apr. 2, 2015, published Oct. 8, 2015 (Publication No. US 2015/0285026), which claims priority to U.S. Provisional Application No. 62/019,679, filed Jul. 1, 2014, U.S. Provisional Application No. 62/003,616, filed May 28, 2014, and U.S. Provisional Application No. 61/974,065, filed Apr. 2, 2014, and a continuation-in-part of U.S. application Ser. No. 13/893,205, filed May 13, 2013. This application is a continuation-in-part of U.S. application Ser. No. 15/355,346, filed Nov. 18, 2016, which is a continuation-in-part of U.S. application Ser. No. 14/132,806, filed Dec. 18, 2013, published Jul. 10, 2014 (Publication No. US 2014/0190685). This application is a continuation-in-part of U.S. application Ser. No. 15/806,826, filed Nov. 11, 2017, published as US 2018/0128073, and is a continuation-in-part of U.S. application Ser. No. 15/672,790, filed Aug. 9, 2017, which claims priority to U.S. Provisional Application No. 62/374,454, filed Aug. 12, 2016, and U.S. Provisional Application No. 62/372,550, filed Aug. 9, 2016. All of these prior applications are herein incorporated by reference in their entirety.

FIELD OF THE INVENTION

Slips for downhole tools and methods of making the same.

BACKGROUND OF THE INVENTION

Slips are elements that engage a casing to hold a downhole tool within the casing. They are movable from an unset to a set position during setting of the downhole tool. When the downhole tool is positioned relative to the casing, a setting tool engaged with the downhole tool is activated causing the slip or slips, which typically encircle the tool's mandrel, to move outward towards the casing. In a set position, the slips, which typically include gripping elements and a body, grip the inner walls of the casing tightly while also engaging the mandrel, to positionally locate the tool with respect to the casing. They are used in bridge plugs, frac plugs, and a number of different types of settable downhole tools.

SUMMARY OF THE INVENTIONS

Applicant discloses a number of inventions relating to slips and cone structures, the composition of slips and cones, and methods for making slips and cones. In some embodiments, a slip is disclosed with a body comprising multiple circumferential segments blued, banded together or interlocking together in a preset position, which is broken into multiple separate segments during setting of the downhole tool. In some embodiments, a slip is shown with a slip body that is split with a full split such that during setting the body does not segment or break up, but expands at the split.

In some inventions and embodiments, gripping structures, such as wickers or buttons, are disclosed for use with slip bodies. In some embodiments, the wickers disclosed and the slip bodies disclosed are configured so that the wickers slide into wicker slots in the slip body (segmented or non-segmented). In some embodiments, the buttons comprise individual cylindrical buttons or button assemblies comprising at least a first and second button extending from a common base.

Any of the bodies or segments of the bodies of the slips or wickers or buttons may be made from degradable or non-degradable, composite or non-composite and/or materials, metallic or non-metallic materials. In some embodiments, metallic degradable materials may comprise aluminum or magnesium alloys. Non-metallic degradable materials may include polymer acids such as PLA or PGA. The degradable nature of the material extends to non-slip elements of the tool, also. Thus, substantially all of the tool may be degradable, in some embodiments, excepting the wickers, buttons or button assemblies, which may be iron or other hard metal or compacted powder metal known in the art. In some embodiments, the buttons and wicker pads may be made from powder metal as set forth in '073 publication and incorporated by reference. The materials may be degradable in natural downhole fluids or fluids that are added to natural downhole fluids. In some embodiments, illustrating the composition and nature of degradability applicable to any structures set forth herein may be found in these two applications incorporated by reference, U.S. application Ser. No. 15/355,346, filed Nov. 18, 2016; and U.S. application Ser. No. 15/403,739, filed Jan. 11, 2017.

A slip for engaging a casing to hold a settable downhole tool within the casing is provided. The slip in a set position at least partially contacts the casing. The slip may comprise, in some embodiments: multiple gripping structures, multiple circumferential segments, the multiple circumferential segments each having a body, each having first and a second side walls, inner and outer walls, and upper and lower walls, the multiple circumferential segments dimensioned to be placed adjacent one another with their side walls generally flush. The circumferential segments cooperate to interlock and couple. In some embodiments, the segments are comprised with a projecting member on the first side wall of a segment of the multiple circumferential segments and a receiving cavity on the second side wall to the segment. The side walls may be configured and the segments arranged, so the multiple coupled segments engage with first and second side walls of adjacent segments to form a ring-shaped slip body. At least some of the outer walls of at least some of the multiple circumferential segments may be configured to receive a least some of the multiple gripping structures so at least some portion of the gripping structure contacts the outer wall of the circumferential segment and at least another portion of the gripping structure stands above the outer wall of the circumferential segment.

In some embodiments, the projecting member may have a dovetail shape and the receiving cavity may comprise walls configured to snugly receive the projecting member. In some embodiments, the bodies of the segments may be comprised of a material that is degradable in a downhole fluid. The degradable material may be a polymer acid. The multiple gripping structures may include one or more wickers or buttons. The cooperating interlocking coupled segments may be configured to break apart when a radially expansive setting force exceeds a minimum breaking force or to deform and bend sufficiently to come apart. The minimum force may be achieved during setting of the tool.

Applicant's invention includes multiple segments each with a pair of side walls in radial planes with respect to a longitudinal axis of the ring formed by the segments. Side walls are configured such that adjacent segments can couple together. The couple may include at least one cavity in the side wall. In one embodiment, a projection in an adjacent side wall fits into—as by sliding—the cavity. In another embodiment, the adjacent side wall has a cavity also and a separate key is inserted to lock the two cavities, and therefore the side walls, together. Thus, in some embodiments (see FIG. 5, for example), the couple is a cavity in one side wall and a projection in an adjacent side wall. In some other embodiments, it may be cavities in adjacent side walls and a key (see FIG. 9D).

In other inventions and embodiments, a gripping device is provided, in some embodiments, comprising: a first split ring slip, the first split ring slip comprising a body having an outer surface and an inner surface, the inner surface having at least a first tapering wall section, and a first perimeter and a second perimeter, the outer surface, in some embodiments, comprising multiple recesses. The first split ring slip may have a full split extending through the body from the outer surface to the inner surface and from the first perimeter to the second perimeter. The first split ring slip may further comprise multiple buttons configured for receipt into the recesses so part of the buttons project outside of the outer surface and part of the buttons engage a wall of the recess.

In some embodiments, the full split may be straight and parallel to the long axis of the tool. The full split may be straight, but angled with respect to the long axis of the tool at a non-normal angle. The full split may include a first section that is straight and parallel to the long axis of the tool, a second section that is straight and perpendicular to the long axis of the tool, and a third section that is straight and parallel to the long axis of the tool but spaced apart from the first section.

In some inventions, a split ring assembly is shown that in some embodiments may comprise: a first split ring slip, the first split ring slip comprising a body having an outer surface and an inner surface, the inner surface having at least a first tapering wall section, and a first perimeter and a second perimeter. The outer surface may comprise multiple recesses. The first split ring slip may have a full split extending through the body from the outer surface to the inner surface and from the first perimeter to the second perimeter. The first split ring slip may have multiple buttons configured for receipt into the recesses so part of the buttons stand above the outer surface and part of the buttons engage a wall of the recess. In some embodiments, a second split ring slip is provided, the second split ring slip comprising a body having an outer surface and an inner surface, the inner surface having at least a first tapering wall section, and a first perimeter and a second perimeter. The outer surface may comprise multiple recesses. The second split ring slip may have a full split extending through the body from the outer surface to the inner surface and from the first perimeter to the second perimeter. The second split ring slip may have multiple buttons configured for receipt into the recesses so part of the buttons project outside of the outer surface and part of the buttons engage a wall of the recess. The first and second split ring slips may be mechanically coupled together so expansion of one during setting will cause the other to expand. The mechanical couple may be a tongue in groove.

BRIEF DESCRIPTION OF THE DRAWINGS

FIGS. 1, 1A, 1B, 2, 2A-2E, 3, 3A, 3B (with wickers) and 4, 5, 6, 7, 8, and 9 (with buttons) illustrate slips having multi-segment bodies with slide-in wickers or buttons, which in some embodiments have bodies which may be made from a material degradable in downhole fluids.

FIGS. 9A, 9B, 9C, 9D, 9D1 and 9E illustrate alternate preferred embodiments of coupling structures.

FIGS. 10, 11, and 12 show a uni-bodied slip, which may be degradable in downhole fluids in some embodiments, with slide-in wickers.

FIGS. 13, 14, 15, and 16 illustrate split ring slips having buttons.

FIG. 17 illustrates an injection molding machine for use in making some embodiments of slips disclosed herein.

FIGS. 17A and 17B illustrate cross-sectional views of gripping elements injection molded into slips, 17A having wickers and 17B having buttons.

FIGS. 18A, 18B, and 18C illustrate wickers for use with multi-segments slips or unibody slips.

FIG. 19 is a cross-sectional view of a slip in either a uni-body or multi-segment configuration.

FIG. 19A illustrates in exploded view the cone and slip body (pre-set) with a notch/groove couple to help guide the slip body as it breaks up during setting.

FIGS. 20A and 20B illustrate an alternate preferred embodiment of a wicker.

FIG. 21 is a cross-sectional view an alternate embodiment of a wicker in either the multi-segmented slip or uni-body slip as disclosed herein.

FIG. 22A illustrates wickers for use in either the multi-segmented slips or uni-body slips disclosed herein.

FIGS. 23A, 23B and 23C illustrate various views of a button assembly for use in either the multi-segment slips or uni-body slips disclosed herein.

FIGS. 24A, 24B and 24C illustrate an alternate preferred embodiment of the button assembly for use with either the multi-segment slips or the uni-body slips disclosed herein.

FIGS. 25 and 25 Detail illustrate an integral assembly typically either load ring and slip, or bottom shoe and slip.

FIGS. 26, 27, and 28 are various views of an alternate embodiment of a multi-segment slip.

FIGS. 29 and 30 illustrate a unibody slip having multiple molded in wickers.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

FIGS. 1, 1A, 1B, 2, 2A-2E, 3, 3A, 3B, 4, 5, 6, 7, 8, and 9 illustrate gripping devices or assemblies, namely, slips 10/11 (two embodiments shown, slips 10 having wicker gripping elements as in FIG. 3A, for example, and slips 11 having button gripping elements as in FIG. 4, for example) having multiple circumferential segments 12/14/16/18/20, each having a first side wall 12 a/14 a and a second 12 b/14 b side wall (only two segments labeled but the others may be the same), an inner wall 12 d/14 d and an outer wall 12 c/12 d, and an upper wall 12 c/14 c and a lower wall 12 f/14 f. in some embodiments, each segment comprises a segment body 15 and a gripping element and structure or shape to allow it to engage an adjacent segment. The multiple circumferential segments are dimensioned to be placed adjacent one another with their side walls generally flush see (FIG. 6) forming a ring-shaped slip body 21, configured to encircle a mandrel.

The slip segments typically include multiple gripping structures, which may be wickers 22 (see FIG. 1A, for example) or buttons 26 (see FIG. 4, for example), which will engage the inner wall of the casing in a set position to set the tool with respect to the casing.

FIGS. 5 and 7 illustrate a cooperating interlocking couple 34 comprising, in some embodiments, a projecting member 30 on the first side wall 12 a of a first segment 12 of the multiple segments and a receiving cavity 32 on the second side wall 12 b flush to an adjacent segment (see FIG. 2B). Receiving cavity 32 has walls configured to snugly receive projecting member 30, as by slideable receipt of one into another down a longitudinal axis of the tool.

The side walls 12 a/12 b may be in a radial plane that passes through the center of curvature of the concentric sections of outer walls 12 c and inner walls 12 d, which is usually at the longitudinal axis of the tool, typically the axis of the mandrel. Excepting the projecting and cavity portions, adjacent side walls (see 12 a and 14 b in FIG. 2B for example) may lay in the same or very close to the same radial plane. Segments 12/14/16/18/20 are arranged so the multiple segments couplingly engage with first and second side walls flush and interlocking with adjacent segments to form ring-shaped slip body 21 (see FIG. 5).

At least some of the outer walls of some of the multiple segments are configured, such as with cutouts, slots, cavities or the like, to receive a least some of the multiple gripping structures so at least some portion of the gripping structures contact the outer wall of the segment and at least another portion of the gripping structure projects outside and above the outer wall of the circumferential segment (see FIG. 3A (wickers) and FIG. 6 (buttons)).

FIGS. 1, 1B, 2 Series, and 3 Series illustrate first embodiment 10 of a multiple piece split ring having multiple partly cylindrical segments, here five 12/14/16/18/20 with wicker 22 gripping elements. A five-piece cylindrical sectioned slip body 21 is shown. However, more or less segments, typically two though eight may be used. In first embodiment 10, wickers 22 are configured to slide into a wicker slot 24 on outer wall 12 c/14 c of at least some of the pieces. Each of the segments is typically similarly or identically shaped so only 12/14 are numbered and shown in detail. Segment 12 has oppositely placed inward canted side walls 12 a and 12 b. Segment 14 likewise has side walls 14 a and 14 b. Segment 12 has outer walls 12 c and inner walls 12 d. Segment 14 likewise has outer/inner walls 14 c/14 d. Uphole or upper wall 12 e and downhole or lower wall 12 f are found on segment 12 with segment 14 having upper/lower walls 14 e/14 f.

The configurations of wickers 22 may vary but slots 24 that receive them may be constructed to snugly receive them. In viewing FIGS. 1B and 2, one may see that a wicker in side view, FIG. 2, may include a body portion 22 a may have a nose 22 c extending therefrom. There may be a top wall 22 b that may be toothed, and a bottom wall 22 d, that may be smooth or non-smooth (see, for example, FIGS. 20A-20B). In some embodiments, side walls 22 e and 22 f may flare outward from top to bottom (see FIG. 1A) to form a dovetail joined with segment body 15. There may be a front wall 22 g and a rear wall 22 h (see FIG. 1A). in some embodiments, bottom 22 d may comprise a base extending outwards from the side walls (see FIG. 2).

FIG. 1A shows that wicker slots 24 may be dovetailed in end view and wickers 22 may be dovetailed to help prevent separation. In some embodiments, wicker slots may be open. The wickers are typically configured for a tight, interference fit with segment body 15. Adhesives 23, such as epoxy, may be used anywhere along the wickers and/or slots to help strengthen the body/wicker joint (see FIG. 1B). In some embodiments, the body segments are injection molded with the wickers in place, to help strengthen the wickers bond to the body (see FIG. 17A, for example). This “engulfs” at least some of the wickers in hot plastic during molding of the segments (see FIG. 17).

FIGS. 2A and 2B illustrate the general structure of Applicant's multi-piece segmented slip in a first embodiment 10. More specifically, viewing FIGS. 2A to 2B, it is seen that a cooperating interlocking couple 34 (see FIG. 2B) is provided which can join adjacent segments, here segment 12 and segment 14. Cooperating interlocking couple 34 may include projecting member 30 of first side wall 12 a of segment 12 to slidably and lockingly engage receiving cavity 32 configured in second side wall 14 b of an adjacent segment, here segment 14. Projecting member 30 may be formed from a projection of the first side wall and, in one shape, as seen in FIG. 2A, is a dovetail shape which provides a locking engagement to resist radial forces of separation that occur during setting of a plug. A dovetail projecting member with receiving cavity configured of walls that will snugly receive such a member will create a lock so the two side walls 12 a and 14 b (see FIG. 2B) will be held flush to one another and resist radial expansion of the assembled and interlocked segments. The paired member/cavity defining cooperating interlocking couple 34 is intended for slidable receipt of the male into the female, slidably along the central axis of the tool. The multi-piece slip is entrained about the mandrel in a ring shape (encircling the mandrel prior to setting (see FIG. 2B).

FIGS. 2C, 2D, and 2E show three “modes” of breakage at cooperating interlocking couple 34 during setting the tool. The couple receives the radially outward directed force of separation and may separate in any mode to uncouple adjacent segments during setting. Rather than breaking, in some embodiments, bending may be sufficient to cause separation.

A multi-segment slip in a first embodiment 10 is shown encircling a mandrel 13 (see FIG. 3A) of a settable downhole tool such as FIG. 3 in U.S. Pat. No. 9,388,662, incorporated herein by reference. The wickers of slip 10, in a set position (see FIG. 3A) at least partially contact casing “C” in which the downhole tool has been run.

FIG. 3A (top slip) shows a multi-segment top slip and shows that wickers 22 can engage the wicker slot 24 where the slot opening is in either the upper or uphole wall 12 e of each of the segments of slip body 21 (may also be open to downhole wall). For the top slip, the wicker and segment body may rest against the top ring when the tool is assembled. In a typical embodiment, the wicker slot and the wicker engagement with the slot may be tapered as seen in FIG. 1, where the slot is widest either at the upper or uphole wall or the lower or downhole wall. In some embodiments, the lower wall for the bottom slip as seen in FIG. 3B may receive the wicker 22 so that when the tool is assembled, a bottom nut or shoe rests against both part of the wicker and part of the segment so as to provide upward force to both during setting.

Turning to FIGS. 4-9, a second embodiment 11 is seen having the same structure and segments, except it is a six segment ring shaped body 21 and instead of having wickers, multiple buttons 26 are provided in multiple button recesses 28 of the outer surface.

FIGS. 4-9 illustrate a multi-segment slip in a second embodiment 11 that differs from the previous embodiment. Instead of wicker gripping elements, multiple buttons 26 are in multiple button recesses 28 on outer walls 12 c (see FIGS. 4 and 5). Inner walls 12 d/14 d (see FIG. 6), as in the previous embodiment 10, may include a tapered section for riding on cones during setting (see FIG. 3B and FIG. 6) and a concentric section-concentric with the outer surface. FIGS. 5 and 6 illustrate upper wall 12 e and lower wall 12 f of what is typically a top slip of a downhole tool having a top and a bottom slip or vice versa for a bottom or bi-directional slip (holds in both directions). In second embodiment 11, the slip comprises multiple segments that slideably engage each other to form a ring in the preset position shown in FIG. 6. This is similar to the previously presented embodiment except it has multiple buttons and button recesses. The buttons may be canted or tilted with respect to a longitudinal axis of the slip in ways known in the art. The buttons may be injection molded with segment bodies 15 (see FIG. 17 Series).

FIGS. 9A, 9B, 9C, 9D, 9D1, and 9E all illustrate alternate embodiments of cooperating interlocking couple for engaging adjacent bodies of the multiple segment ring. FIG. 9A illustrates couple 34 a with interlocking notches 35/37 in adjacent segment bodies 15 which flushly and closely engage one another, the notches being reversed on opposite side walls as seen in FIG. 9A. FIG. 9B illustrates coupling 34 b comprising projecting member 30 in cavity 32 having a different shape than the dovetail illustrated in FIG. 1A, for example. Here, projecting member is a partially spherical shape (greater than a hemisphere but less than a full sphere) and cavity 32 mirrors the shape of the projecting member. Both dovetail and partially (greater than a hemispherical shape) provide interlocking capability. FIG. 9C shows multiple dovetail projecting members on a sidewall for engaging multiple cavities in an adjacent sidewall. That is to say, multiple couple 34 c on each coupling sidewall pair.

The embodiments illustrate independent segments of a ring assembled by configuring walls that lay in one or more radial planes extending outward from a longitudinal axis of the ring and forming segment side walls. Walls can be configured with a projection meeting a cavity (see, for example, FIGS. 5 and 7) or two cavities that may face one another and receive a “key” (see FIG. 9D). FIG. 9D illustrates a key couple 34 d, where a separate key 33 (see FIG. 9D1), which may be paired, joined, dovetails, is used and configured to snugly attach two adjacent segment bodies by sliding into each cavity 32 when the adjacent sidewalls are held flush together. The two cavities aligned with one another to provide a key-shaped outline. Moreover, key 33 can be made of a different material, harder or softer, more brittle, less brittle, degradable, non-degradable, metallic, nonmetallic, as compared to the composition of the body segments. Moreover, key 33 may include a waist 33 a that may be made narrower or wider and, therefore, allow one to control the breakability or bendability of the slip as the segments separate during the setting process. For example, if one wanted the segments to break apart earlier in the setting process, the waist 33 a could be made narrower or the material comprising key 33 may be made to break easier. In one embodiment, key 33 is metallic and made of an aluminum or magnesium or other metal degradable in a downhole fluid. The key and the cutouts or cavities into which it is received may narrow along a longitudinal axis for a one-way fit. There may be multiple key couples 34 d.

FIG. 9E illustrates that a segment body, unlike the embodiment in FIG. 7, may be two different forms. That is to say, in viewing a segment of FIG. 7, it can be appreciated that one single injection mold can be used to make all the segments or a ring—each segment is identical in shape and dimension. That is because, in some embodiments, one side wall has a projecting member and the other side wall of the same segment has a cavity. Thus, all four, five, six or whatever number of segments are used to make up a ring can be made from a single mold, as by, for example, injection molding as set forth herein. However, the embodiment of the coupling illustrated in FIG. 9E is the same, that is, a dovetail projecting member in a dovetail shaped cavity. However, there are two different molds required, one for a segment having two projecting members and another mold required to mold a segment having two cavities. Adhesive may be used at any coupling joint so that in assembled pre-set configuration of the ring, it will not slide apart into separate segments. The use of multiple segments allows the use and ability to choose all buttons, all wickers or mixing in the same slip, buttons on some segments and wickers on others. The use of the key couple 34 d of FIG. 9D allows the user to be selective from keys of various compositions. Some keys may be stronger than others and may release (break) at different pressures encountered during setting. Thus, a user may select all keys of a given strength suited for a particular need.

In some embodiments, the slip segment bodies are made of an injection moldable composition, such as polyglycolic (PGA) or polylactic acid (PLA) or other polymer acid which may be degradable in downhole tools. One such PGA is Kuredux by Kureha. In some embodiments, the segment bodies may be composite materials, which may be machined. Herein a composite material refers to engineered materials made from two or more constituent materials with significantly different physical or chemical properties and which remain separate and distinct within the finished structure. Composite materials are well known to one of ordinary skill in the art and may include, for example, and without limitation, a reinforcement material, such as fiberglass, quartz, kevlar, Dyneema or carbon fiber combined with a matrix resin, such as polyester, vinyl ester, epoxy, polyimides, polyamides, thermoplastics, phenolics, or combinations thereof. In an embodiment, the composite is a fiber reinforced polymer. At least some of these composites may be used in injection molding.

FIGS. 10-12 illustrate a non-segmented or unibody slip 27 in which wickers 22 “T” shaped in end views, slide into “T” shaped slots 25 in the integral (non-segmented) body. The integral or unibody slip may receive the wicker in multiple wicker slots 25, which are configured with a narrow end and a wide end and in which the similarly shaped wickers are designed to be snugly engaged with an interference fit (adhesives may be used to help joint integrity). The “T” is seen to have thicker walls above the arms than below (see FIG. 10). These figures show “Y” shaped notches, in some embodiments, 29 in the walls of the integral (in the preset position) body with the leg of the “Y” extending only part way through from outer wall to inner wall. Multiple holes 31 may be used to weaken the joint to help separation during setting.

Other casing gripping devices are illustrated in FIGS. 13-16 and comprise an at least first split ring slip 100 as seen in FIGS. 13 and 14. These slips are configured to expand during the setting process, but not breaking into multiple pieces. In some embodiments, they may be made of a metal, including an alloy such as aluminum alloy. In some cases, the metal may be dissolvable in downhole fluids so no milling is required. The first split ring slip may have a body 102 having an outer surface 108 and an inner surface 110. The inner surface may have at least a first tapering wall section 110 a, and optionally a second tapering wall 110 b and cylindrical (concentrical) walls 110 c, a first perimeter 112 and a second perimeter 114. In some embodiments, the cylindrical walls can include webs or cutouts 110 d to help body 102 to expand during setting without breaking. Unlike conventional slips which break during setting, these split ring embodiments are configured to expand at the split rather than break during setting. The outer surface may comprise multiple button recesses 106 for receiving buttons 104. First split ring slip 100 may have a complete or full split 116 extending through body 102 from outer surface 108 to inner surface 110 and from first perimeter 112 to second perimeter 114. First split ring slip 100 may further include multiple buttons 104 configured for receipt into recesses 106 such that part of the button stands above the outer surface and part of the button is engaging a wall of the recess. In some embodiments, connecting necks 105 may be provided across opposing walls of the full split to help resist pre-setting of the slips or inadvertent slip expansion. These necks may simply be areas where a machined cut is omitted or they could be areas where an adhesive bond is added after the split is cut.

Another similar split ring casing gripping device, split ring slip assembly 200, is illustrated in FIGS. 15 and 16 comprising a first split ring slip 202 and a second split ring 204. First split ring slip 202 may include a body 206 having an outer surface 212 and an inner surface 216. Inner surface 216 may have at least a first frusto-conical tapering wall sections 216 a/218 a. Body 206 may have a first perimeter 220 and a second perimeter 224. Outer surface 212 may comprise multiple recesses 212 a for receipt of buttons 210. First split ring slip 202 may have a full splits 228/230 extending through the body from the outer surface to the inner surface and from the first perimeter to the second perimeter.

First split ring slip 202 may further comprise multiple buttons 210 configured for receipt into recesses 212 a, so part of the button projects above the outer surface and part of the button engages a wall of the recess. Full split 228 may be straight and parallel to the long axis of the tool (not shown). The full split may be straight, but angled with respect to the long axis of the tool at a non-normal angle (see FIG. 15). The full split may include a first section that is straight and parallel to the long axis of the tool, a second section that is straight and perpendicular to the long axis of the tool, and a third section that is straight and parallel to the long axis of the tool but spaced apart from the first section (see FIG. 13).

As seen in FIGS. 15 and 16, split ring assembly 200 may include a second split ring slip 204, the second split ring slip comprising a body 208 having an outer surface 214 and an inner surface 218, the inner surface having at least a first frusto-conical tapering wall section 218 a. Body 208 has a first perimeter 222 and a second perimeter 226. Outer surface 214 may comprise multiple recesses 214 a. Second split ring slip 204 may have a full split 230 extending through the body from the outer surface to the inner surface and from the first perimeter to the second perimeter. Second split ring slip 204 may further comprise multiple buttons 210 configured for receipt into recesses 214 a, so part of the button stands above the outer surface and part of the button is engaging a wall of the recess. The two split ring slips 202/204 may, in some embodiments, be mechanically coupled together so expansion of one during setting may cause the other to expand. In some embodiments, this is achieved with tongue 232 on second perimeter wall of body 208 engaging groove 234 on second perimeter wall 224 of body 206 forming a mechanical couple between the adjacent slip bodies.

FIG. 17 illustrates an injection molding machine 300 for injection molding segments of the multi-segmented body (see for example FIG. 1A) or a unibody (see for example FIG. 10), which unibody may contain wicker pads 22. Injection molding machine 300 may include an injection unit 302 and a clamping unit 304. Clamping unit 304 may include a mold 306, typically having a first part 306 a and a second part 306 b, one part moveable with respect to the other. A feed hopper 308 contains feedstock 312. The auger is heated and feedstock is forced through the heated auger and, being of a plastic nature, forced through the nozzle into the mold. After cooling, the mold is separated and injector pins can knock out the cooled, molded piece.

Buttons 26 and wickers 22 may become an integral part of the slip segment by injection molding, in some embodiments, through the process of over-molding or insert molding. These processes allow a variety of inserts molded into the plastic body: wickers, buttons, button assemblies, keys or the like. Either way or any other way known in the art of molding, gripping elements may be an integral part and, as the plastic feedstock cools, will be integrated into and part of the body of the segment as part of a single molding process.

Feedstock 312 may have multiple parts. In some embodiments, part of feedstock 312 may be a plastic part 312 a, such as pellets or other, thermoplastic, such as: nylon, TPU, TPE, PLA, PPSL, PLGA, PGA or PEEK. Some are all millable and/or degradable. Feedstock mayh be composite, a thermoplastic material, and a non-thermo-plastic material. The thermoplastic may be long chain, melt processable plastic, with or without fibers. The fibers may be long chain filaments, such as polymer. The body may be injected molded of nylon, PEEK or other suitable tough material. The body and gripping elements may be made from millable materials such as nylon for the body and powder metal for the gripping elements. Another portion of feedstock 312 may be tough, durable chopped up lengths of fibers 312 b. Fibers 312 b may be short, chopped up glass fibers, such as those used for reinforcement in composites for downhole tool structural applications. The fiber may be formed from a degradable polymer, such as a polylactide or polyanhydride. The fiber may be a degradable or non-degradable fiber. Other fibers that may be used are glass, carbon, and polyester. The feedstock may include other materials 312 c, which other materials may modify the property of the thermoplastic or the bonding of the thermoplastic to the fibers, or serve any other purpose.

All of the materials that comprise the integral body, including wicker 22 and the segment body, may be chosen from suitable degradable materials, that is, materials degradable in a natural or artificially modified downhole fluid, as set forth in the patents or publications incorporated herein by reference. Typically, in some embodiments, wicker 22 will be tough, durable metallic, aluminum, iron, magnesium or the like, which may or may not be degradable. Slip bodies may be comprised of a non-degradable or degradable thermoplastic with optionally a non-degradable degradable fiber, such as those known in the art of degradable composites. Notice in FIG. 17A, the dovetail nature of the joint between the body and the wicker 22, which further enhances integrity of the joint. The body may be made of a degradable material that will dissolve quickly enough in natural aqueous downhole fluid in the well having a pH less than about 7 so within less than five days after the tool is immersed in the well's wellbore fluid, the body dissolves enough without milling out the tool, retrieval of the tool from the well or other intervention on the tool from the surface, so the tool ceases to isolate the zone above the tool from a zone below the tool, and the tool does not prevent beginning production from below the tool.

FIGS. 17A and 17B illustrates a partial section of a segment 12/14/16/18/20 with the wicker 22 (FIG. 17A) or buttons 26 (FIG. 17B) in body 15 molded integrally thereto as, for example, by over-molding or insert molding. FIG. 17B illustrates bodies 12/14/16/18/20 (sometimes “bodies 12-20”) of segments having buttons 26 molded there into. Note that, like the dovetail nature of the joint between the wicker 22 and the slip body as illustrated in FIG. 17A, there is also an overlap with the top surface of the buttons partially covered by the body during the injection molding process to help further secure the engagement of the button to the body. In some embodiments, wickers 22 and buttons 26 are made of powder metal, including part of powder metal that may be carbonitrited or, as found in application Ser. No. 15/806,826, incorporated herein by reference, now US Publication No. 2018/0128073.

FIGS. 18A, 18B, and 18C illustrate various views of a wicker 422 that is composite in profile comprising a rectangular section and a triangular section (see FIG. 18B for example) with dashed lines. This is another shape for a wicker that may be formed integrally into an injection molded body as seen in FIG. 17A or FIG. 19. Turning back to the FIG. 18 series, it is seen that wicker 422 may have a long axis. Moreover, there may be multiple transverse cavities 426 a in bottom surface 426 to the longitudinal axis as seen in FIG. 18B, and transverse cavity 430 a in wide end wall 430. FIGS. 18A and 18B show bottom surface 426 and FIG. 18A as seen from the rear it is seen that bottom surface 426 may also define a longitudinal cavity 426 b. Top surface 424 may include teeth 424 a and narrow end 428 may be truncated as seen in FIG. 18B. Transverse channels 580 may also be present (see FIGS. 19 and 30).

FIGS. 20A and 20B illustrate another wicker 422 a with a different arrangement of cavities and FIG. 21 illustrates a manner in which the wicker pad is molded into slip body 402 (see FIG. 21). FIGS. 19 and 22A illustrate notches or weakened areas 440 weakened by cut out areas, that provide controlled breakage of the uni-body slip during expansion (setting). It is also understood that weakened area 440 may be where cooperating interlocking couple 34 (see FIG. 2B)—male and female or key is located between flush adjacent walls of the multi-segmented embodiment set forth herein. It is seen in FIG. 21 that in some embodiments, cavities 426 a in the floor 426 are straight-walled (see FIG. 21) or curved wall (see FIG. 18B). It is also seen that, for example, in reference to FIG. 21, the tapered portion of the inner surface of the slip body mirrors the tapered portion of the lower surface of the wicker and the flat (or concentric portion) of the inner surface of the slip body mirrors the flat portion of the lower surface of the wicker.

FIGS. 19 and 19A illustrate wickers 422 injection molded into a slip body 402 with inner surface 406 to define a slip 400 which is similar to the slip seen in FIGS. 10-12 for example. However, slip 400 may also have a slip body comprised of multiple segmented bodies and similar to the embodiment illustrated in FIG. 1. The one difference in FIG. 19 is primarily in one or more anchor members 412 on the slip body which will extend into the wicker to help lock the wicker pads into place and prevent them from being dislodged when the slip is set. Any of the wicker shapes can be used in any of the uni-body or multi-segment slip bodies disclosed herein. It is seen in FIG. 19 that only an uppermost portion of teeth 424 a are seen to extend above the outer surface 404 and troughs 424 b are at least partly filled with thermoplastic material. Again, partially filling the teeth troughs with thermoplastic during injection molding as well as providing anchor members 412 and a perimeter at the front and the back ends helps lock the wicker pad in place and hold it there when the set tool is subject to forces such as during fracing. FIG. 19A illustrates projections 441 on cone for engaging notches or weakened areas 440, that will help guide the segments of the slip during setting.

FIGS. 23A, 23B and 23C illustrate views of a button assembly 460 comprising at least a first button 464 and a second button 466 attached or affixed to and generally perpendicular to a base 462. Buttons 464/466 have top surfaces 464 a and 466 a and during injection molding, as seen in FIG. 23C, there may be overlap of plastic on the top surfaces of one or both of the buttons in a preferred embodiment and full encapsulation of the base in the thermoplastic. This will help prevent tipping or coming loose the buttons during setting or pressurizing of the set tool and the casing.

FIGS. 24A, 24B and 24C illustrate an alternate embodiment 460 a of a button assembly. Here one difference is that top surfaces 464 a and 466 a are inclined instead of perpendicular and base 462 a has a thickness that varies longitudinally from narrow to thick and multiple cavities 468. FIG. 24C shows the alternate button assembly injection molded integrally into thermoplastic with overlap areas of the plastic onto the top surface and the manner in which the plastic fills the cavities to help lock the button assembly into place and also illustrating base 462 totally embedded in the slip body. Also, one may appreciate with respect to FIG. 24C that the bottom surface of the button assembly may be tapered to mirror the ramp on the inner wall of the slip body. Comparing FIG. 23C to FIG. 24C, one may appreciate that there is greater surface area between the base and the slip body by providing the cavities which may contribute to a stronger bond between the slip and the gripping element.

FIG. 25 illustrates a settable downhole tool having an integral assembly 509 that may comprise a combination load ring 502/slip 504, integral assembly 513 or a bottom shoe 507/slip 505, integral assembly 509. Integral assemblies 509 and 513 may be injection molded as a single unit with neck or necks 511 between the load ring and slip or bottom shoe and slip. The neck may be bendable or breakable during setting of the tool. Integral assembly 509 or 513 may be both less expensive to manufacture and easier to assemble. Integral assembly 509 or 513 is not limited to the particular slips or any other structure disclosed herein, but may be used with any elements, adjacent to a slip in a preset position and suitable for injection molding. The integral slip—connector neck may be used adjacent any mandrel encircling structural element that lays adjacent the slip in a pre-set condition. The connector neck may be thin, in some embodiments, less than 1″ in diameter, or less than ¼″ in diameter, so they break when the tool sets and the slips are forced outward. The integral slip/neck/structural element may be injection molded in one or multiple steps.

FIGS. 26, 27, and 28 illustrate an alternate embodiment of a multi-segment slip 550. In this embodiment, multiple slip bodies 552 have flush side walls 552 a. They are assembled using a bonding agent, an adhesive or a glue 556 between adjacent side walls and in addition have tight bands 554, typically two, but in some embodiments, only a single band, which helps hold the multiple segments together in a preset position. Slip bodies 552 are seen to have side walls 552 a, inner walls/ramp 552 b, and inner walls/cylindrical 552 c, which inner walls will meet typically flush with appropriate cones to guide the multi-segmented slip during the tool setting operation. Multi-segmented slip may have an outer surface/central 552 d for receipt of multiple buttons 558 there into. Multi-segmented slip 550 may also have an outer wall/first edge/notched 552 e and an outer wall/second edge/notched 552 f for receipt of the composite bands tightly there into, such that an outer surface of the band is flush with outer surface/central 552 d of the slip, and a front edge surface of each of the composites is flush with an edge surface of the multi segmented slip. The buttons may be made from any material disclosed herein this application or known in the prior art. The multi segmented bodies 552 and the bands 554 may be made of any known degradable or non-degradable, metallic or nonmetallic, moldable or non-moldable, composite or non-composite material disclosed herein or as known in the art.

FIGS. 29 and 30 illustrate another embodiment of a slip, in this case, a unitary slip 570 rather than one that is made, preset, from multiple bodies. In FIG. 29, slip 570 is typically comprised of any injection moldable material, degradable or non-degradable, composite or non-composite or any other suitable injection moldable material. Wickers 574 (see FIG. 30) may be injection molded into the slip, which wickers may include wicker teeth 576, and a configured wicker floor 578 and transverse channels 580 through the wicker body from one side wall 574 a to the other side wall 574 b. The wickers are placed in an injection mold and the composite or other thermoplastic material are injection molded around the wickers so, in some embodiments, just the teeth are left exposed.

Although the invention has been described with reference to a specific embodiment, this description is not meant to be construed in a limiting sense. On the contrary, various modifications of the disclosed embodiments will become apparent to those skilled in the art upon reference to the description of the invention. It is therefore contemplated that the appended claims will cover such modifications, alternatives, and equivalents that fall within the true spirit and scope of the invention

The present invention is adapted to attain the ends and advantages mentioned as well as those that are inherent therein. The embodiments disclosed above are illustrative only, as the present invention may be modified and practiced in different but equivalent manners apparent to those skilled in the art having the benefit of the teachings herein. No limitations are intended to limit the details of construction or design shown, other than as described in the claims below. The illustrative embodiments disclosed above may be altered or modified and all such variations are considered within the scope and spirit of the present invention.

The terminology used herein is for the purpose of describing particular implementations only and is not intended to be limiting. The singular form “a”, “an”, and “the” are intended to include the plural forms as well, unless the context clearly indicates otherwise. The terms “comprises” and/or “comprising,” when used in the this specification, specify the presence of stated features, integers, steps, operations, elements, and/or components, but do not preclude the presence or addition of one or more other features, integers, steps, operations, elements, components, and/or groups therefore. Compositions and methods described in terms of “comprising,” “containing,” or “including” various components or steps, can also “consist essentially of or “consist of the various components and steps.

Whenever a numerical range with a lower limit and an upper limit is disclosed, any number and any included range falling within the range is specifically disclosed. Every range of values (of the form, “from about a to about b,” or, equivalently, “from approximately a to b,” or, equivalently, “from approximately a to b”) disclosed herein is to be understood to set forth every number and range encompassed within the broader range of values. The terms in the claims have their plain, ordinary meaning unless otherwise explicitly and clearly defined by the patentee. If there is any conflict in the usages of a word or term in this specification and one or more patent(s) or other documents that may be incorporated herein by reference, the definitions that are consistent with this specification should be adopted.

The corresponding structure, materials, acts, and equivalents of all means or steps plus function elements in the claims below are intended to include any structure, material, or act for performing the function in combination with other claimed elements as specifically claimed. The description is presented for the purposes of illustration and description, but is not intended to be exhaustive or limited to the implementations in the form disclosed. Many modifications and variations will be apparent to those of ordinary skill in the art without departing from the scope and spirit of the disclosure. The implementations were chosen and described in order to explain the principles of the disclosure and the practical application and to enable others or ordinary skill in the art to understand the disclosure for various implementations with various modifications as are suited to the particular use contemplated. Those skilled in the art will readily recognize that a variety of additions, deletions, modifications, and substitutions may be made to these implementations. Thus, the scope of the protected subject matter should be judged based on the following claims, which may capture one or more concepts of one or more implementations. 

1. A slip for use about a mandrel of a settable downhole tool, the slip configured to hold the tool within a casing when the slip is in a set position, the slip comprising: multiple circumferential segments, each segment having a first side wall and a second side wall, an inner wall and an outer wall, and an upper wall and a lower wall, the multiple circumferential segments configured to be placed adjacent each other; multiple gripping structures; cooperating interlocking couple comprising a projecting member on a side wall of a segment of the multiple circumferential segments and a receiving cavity on another side wall to an adjacent segment; wherein the side walls are configured and the segments arranged, so the multiple coupled segments engage flush with adjacent segments to form a ring-shaped slip body; and wherein at least some of the outer walls of at least some of the multiple circumferential segments are configured to receive a least some of the multiple gripping structures such that at least some portion of the gripping structure contacts the outer wall of the circumferential segment and at least another portion of the gripping structure stands above the outer wall of the circumferential segment.
 2. The slip of claim 1, wherein the projecting member is a dovetail and the receiving cavity comprises walls configured to snugly receive the projecting member.
 3. The slip of claim 1, wherein the circumferential segments comprise a material that is degradable in a downhole fluid.
 4. The slip of claim 3, wherein the degradable material is a polymer acid.
 5. The slip of claim 1, wherein the multiple gripping members include multiple buttons.
 6. The slip of claim 1, wherein the multiple gripping members include a button assembly.
 7. The slip of claim 1, wherein the multiple gripping members include a wicker.
 8. The slip of claim 1, wherein the cooperating interlocking couple is configured to break apart when a radially expansive force exceeds a minimum force, wherein the minimum force is achieved during setting of the tool.
 9. The slip of claim 1, wherein the cooperating interlocking couple is configured to bend and come apart when a radially expansive force exceeds a minimum force, wherein the minimum force is achieved during setting of the tool.
 10. The slip of claim 8, wherein the minimum force is at least 100 psi.
 11. The slip of claim 1, wherein the multiple circumferential segments are identical.
 12. The slip of claim 1, further including an adhesive between adjacent side walls.
 13. The slip of claim 1, wherein the multiple circumferential segments are comprised of an injection undegradeable material.
 14. The slip of claim 1, wherein the multiple circumferential segments are identical; and wherein the multiple circumferential segments are comprised of an injection undegradeable material.
 15. The slip of claim 1, wherein the multiple gripping structures are wickers; and wherein the outer walls of the multiple segments are configured to receive the wicker pads.
 16. The slip of claim 15, wherein the outer walls are configured for an interference fit.
 17. The slip of claim 1, wherein at least some of the multiple gripping structures are injection molded with a circumferential segment.
 18. A gripping device for use about a mandrel of a settable downhole tool, the gripping device configured to engage a casing when the tool is in a set position, the gripping device comprising: a first split ring slip, the first split ring slip comprising a body having an outer surface and an inner surface, the inner surface having at least a first tapering wall section, and a first perimeter and a second perimeter, the outer surface comprising multiple recesses, the first split ring slip having a split extending through the body from the outer surface to the inner surface and from the first perimeter to the second perimeter, the first split ring slip further comprising multiple buttons configured for receipt into the recesses such that part of the button stands above the outer surface and part of the button is engaging a wall of the recess; wherein, during setting, a width of the split expands.
 19. The gripping device of claim 18, wherein the split is straight and parallel to the long axis of the tool.
 20. The gripping device of claim 18, wherein the split is straight, but at a non-normal angle with respect to a long axis of the tool.
 21. The gripping device of claim 18, wherein the split includes a first section that is straight and parallel to a long axis of the tool, a second section that is straight and perpendicular to the long axis of the tool, and a third section that is straight and parallel to the long axis of the tool but spaced apart from the first section.
 22. The gripping device of claim 18, wherein the split is a full split.
 23. The gripping device of claim 18, further including neck connectors.
 24. A split ring assembly for use about a mandrel of a settable downhole tool configured to engage a casing when the tool is in a set position, the split ring assembly comprising: a first split ring slip, the first split ring slip comprising a body having an outer surface and an inner surface, the inner surface having at least a first tapering wall section, and a first perimeter and a second perimeter, the outer surface comprising multiple recesses, the first split ring slip having a split extending through the body from the outer surface to the inner surface and from the first perimeter to the second perimeter, the first split ring slip further comprising multiple buttons configured for receipt into the recesses so part of at least some of the buttons project outside of the outer surface and part of at least some of the buttons engage a wall of a recess; and a second split ring slip, the second split ring slip comprising a body having an outer surface and an inner surface, the inner surface having at least a first tapering wall section, and a first perimeter and a second perimeter, the outer surface comprising multiple recesses, the second split ring slip having a split extending through the body from the outer surface to the inner surface and from the first perimeter to the second perimeter, the second split ring slip further comprising multiple buttons configured for receipt into the recesses such that part of the button stands above the outer surface and part of the button is engaging a wall of the recess; wherein the first and second split ring slips are mechanically coupled together so expansion of one of the first or second split radially outward movement during setting may cause the other to expand.
 25. The split ring assembly of claim 24, wherein the mechanical couple is a tongue in groove.
 26. The split ring assembly of claim 24, wherein the splits are full splits.
 27. A settable downhole tool for use in a casing comprising: a mandrel; a sealing element; a slip; a structural element that lays adjacent to the slip when the tool is in an assembled and pre-set condition; wherein the structural element and slip are integral as a result of a connector neck between them, in a pre-set and run in condition.
 28. The settable downhole tool of claim 27, wherein the connector neck is configured to break when the tool sets in the casing.
 29. The settable downhole tool of claim 27, wherein the structural element, slip and connector neck are comprised of an injection moldable material.
 30. The settable downhole tool of claim 27, wherein the structural element, slip and connector neck are injection molded from a composition that is degradable in a downhole fluid.
 31. The settable downhole tool of claim 27, wherein the structural element, slip and connector are injection molded.
 32. A slip for use about a mandrel of a settable downhole tool, the slip configured to hold the tool within a casing when the slip is in a set position, the slip comprising: multiple circumferential segments, each segment having a first side wall and a second side wall, an inner wall and an outer wall, and an upper wall and a lower wall, the multiple circumferential segments configured to be placed adjacent each other; at least one band for holding the multiple segments into a ring such that adjacent side walls are flush to one another.
 33. The slip of claim 32, further including a bonding agent for bonding adjacent side walls.
 34. A slip assembly for use in a downhole settable tool, the slip assembly comprised of segments configured to hold the tool within a casing when the tool is set within the casing, the assembly comprising: a ring comprising multiple segments; each segment having a receiving circumferential side and an opposite projecting circumferential side; each receiving side has an inward slot for circumferentially holding a projection from an adjacent segment's projecting side; each projecting side has an outward projection for being circumferentially held within the slot of an adjacent segment's receiving side; each segment's receiving side is coupled with the projecting side of the adjacent segment by the projecting side's projection being circumferentially held within the receiving side's slot; the multiple coupled segments comprise a ring of circumferentially coupled segments configured to be located about the tool's mandrel; and the ring is circumferentially and radially expandable responsive to outward radial force on the inner radial side of the ring when the tool is set within the casing, wherein at least some of the circumferential expansion will occur by at least some of the projection within slot couplings decoupling, and the decoupled segments circumferentially expanding relative to each other and radially expanding toward the casing.
 35. The assembly of claim 34, wherein each slot extends only part way through the segment from one side or face of the segment and does not open to an opposing side or face of the segment.
 36. The assembly of claim 34, wherein the slot of a first segment is an axial slot which opens to a first axial face of the first segment; and the projection of an adjacent second segment is a axial projection which is slidably axially positioned into the first segment's slot through the slot's opening to the first segment's first axial face.
 37. The assembly of claim 36, wherein the slot has a first axial end opening to the first axial face and a second axial end opening to a second opposing axial face, the slot is a continuous slot from the first axial end to the second axial end, and the first axial end of the slot is wider than the second axial end of the slot; the projection of the adjacent second segment has a first axial end and a second axial end and the first end of the projection is narrower than the second end of the projection, the first end of the projection is narrower than the first end of the slot and the projection is configured to be capable of slidably fitting into the slot through the slot's first end, and the second end of the projection is wider than the first end of the slot and holds the projection within the slot against the projection sliding entirely outside of the slot through the slot's first end.
 38. The assembly of claim 34, wherein: at least some of the segments are injection molded segments and are identical to at least some of the other segments; the segments are configured so each segment can be coupled with each of the other segments in any segment order to comprise the ring of segments; and each segment's projection is configured to slide into each circumferentially adjacent segment's slot, each segment's projection is configured to be circumferentially held within each adjacent segment's slot, and the multiple circumferentially coupled segments comprise the ring of multiple segments.
 39. The assembly of claim 34, wherein: the slot of a first segment is a radial slot which opens to an inner radial face of the first segment; and the projection of an adjacent second segment is a radial projection which is slidably radially positioned into the first segment's slot through the slot's opening to the first segment's inner radial face.
 40. The assembly of claim 39, wherein: the slot has an inner radial end opening to the inner radial face and an outer radial end opening to a second opposing radial face, the slot is a continuous slot from the inner radial end to the outer radial end, and the inner radial end of the slot is wider than the outer radial end of the slot; the projection of the adjacent second segment has an inner radial end and an outer radial end, and the outer end of the projection is narrower than the inner end of the projection, the outer end of the projection is narrower than the inner end of the slot, and the projection is configured to be capable of slidably fitting into the slot through the slot's inner end, and the inner end of the projection is wider than the outer end of the slot and holds the projection within the slot against the projection sliding entirely outside of the slot through the slot's outer end.
 41. The assembly of claim 347, wherein a multiplicity of the segments are identical to each other.
 42. The assembly of claim 27, wherein: all of the assembly's segments' slots are shaped and angled similarly, all of the segments projections are shaped and angled similarly, and all of the assembly' segments' slots and projections are angled similarly, the similarity of shapes and angles being similar enough so all of the assembly's segments may be interchangeably coupled to form a ring about the downhole tool's mandrel, each segment having a projection circumferentially held within an adjacent segment's slot, the multiple circumferentially coupled segments forming a circular ring of segments for use about the mandrel.
 43. The assembly of claim 42, wherein all of the segments are identical to each other.
 44. The tool of claim 34, wherein the segments will degrade quickly enough in natural aqueous downhole fluid in the well having a pH less than 7 so within less than five days after the tool is immersed in the well's wellbore fluid, the segments dissolve enough without milling out the tool, retrieval of the tool from the well or other intervention on the tool from the surface, so the tool ceases to isolate a zone above the tool from a zone below the tool, and the degraded segments do not prevent beginning production of hydrocarbons from below where the tool was set in the casing.
 45. The assembly of claim 34, wherein each segment comprises: a body having an outer radial face and an inner radial face, a first axial side and a second axial side; a wicker slot located in the outer radial face and the first axial slide side, the first axial side portion of the slot opening to the inner radial face and the outer radial face, and the outer radial face portion of the slot opening to the first axial side and the outer radial face; the outer radial portion of the slot narrows as it extends from the first axial side toward the second axial side; a wicker insert comprised of a wicker material which is harder than a body material comprising the body, the outer face of the wicker having teeth for gripping the casing, the wicker configured to be closely held within the wicker slot; the wicker is closely held within the wicker slot, the wickers teeth configured so upon setting the tool in the casing, the wicker's teeth will grip the casing and provide greater resistance against axial movement of the tool in the direction of the first axial side than resistance against axial movement of the tool in the direction away from the first axial side; an upper face of the body at the first axial side portion of the slot holds the wicker within the body against movement of the wicker in the direction of the second axial side; and the narrowing outer radial face portion of the slot holds the wicker against movement of the wicker in the direction of the second axial side.
 46. A slip assembly for use in a downhole settable tool, the slip assembly comprised of segments configured to hold the tool within a casing when the tool is set within the casing, the assembly comprising: a ring comprising multiple segments; each segment having a receiving circumferential side and an opposite projecting circumferential side; each receiving side has an inward slot for circumferentially holding a projection from an adjacent segment's projecting side; each projecting side has an outward projection for being circumferentially held within the slot of an adjacent segment's receiving side; each segment's receiving side is coupled with the projecting side of the adjacent segment by the projecting side's projection being circumferentially held within the receiving side's slot; all of the assembly's segments' slots are shaped and angled similarly, all of the segments projections are shaped and angled similarly, and all of the assembly' segments' slots and projections are angled similarly, the similarity of shapes and angles being similar enough so all of the assembly's segments may be interchangeably coupled to form a ring about the downhole tool's mandrel, each segment having a projection circumferentially held within an adjacent segment's slot, the multiple circumferentially coupled segments forming a circular ring of segments for use about the mandrel; at least some of the segments are injection molded segments and are identical to at least some of the other segments; the segments are configured so each segment can be coupled with each of the other segments in any segment order to comprise the ring of segments; and each segment's projection is configured to slide into each circumferentially adjacent segment's slot, each segment's projection is configured to be circumferentially held within each adjacent segment's slot, and the multiple circumferentially coupled segments comprise the ring of segments; the multiple coupled segments comprise a ring of circumferentially coupled segments configured to be located about the tool's mandrel; the ring is circumferentially and radially expandable responsive to outward radial force on the inner radial side of the ring when the tool is set within the casing, wherein at least some of the circumferential expansion will occur by at least some of the projection within slot couplings decoupling, and the decoupled segments circumferentially expanding relative to each other and radially expanding toward the casing; and the segments will degrade quickly enough in natural aqueous downhole fluid in the well having a pH less than 7 so within less than five days after the tool is immersed in the well's wellbore fluid, the segments dissolve enough without milling out the tool, retrieval of the tool from the well or other intervention on the tool from the surface, so the tool ceases to isolate a zone above the tool from a zone below the tool, and the degraded segments do not prevent beginning production of hydrocarbons from below where the tool was set in the casing. 